A. Field of the Invention
The invention relates to apparatus for obtaining tissue samples from body cavities of animals, particularly from the endometrial cavity of a human female.
B. Description of the Prior Art
In the routine cytopathological evaluation of the cervical-vaginal smear, the endocervical and endometrical components of the smear comprise a very small portion of the slide or may even be completely absent. Since post-menopausal mucous is usually very thick, tenacious, and essentially seals the endocervical canal, it is very difficult, and in many instances virtually impossible, for the efoliated endometrial cells to reach the vaginal pool. Consequently, these cells are rarely available in sufficient content when conducting a routine cervical-vaginal smear evaluation. The cervical-vaginal smear is a screening device for the detection of cervical cancer (neoplasia) or other hormonal changes.
Several techniques exist for the withdrawal of endometrial tissue for diagnosing endometrial neoplasia. However, these have proven to be complex, time consuming or have been of questionable diagnostic value. Some of these techniques have been acceptable by patients. However, the techniques are complex, unreliable, and expensive. Some examples of these techniques are commonly referred to as brush techniques, aspiration techniques, and jet washing techniques. Most of these techniques depend upon suspension of the obtained specimen of endometrial mucous and cells in a solution to dissolve or separate unwanted substances and subsequently separating the cells from the solution by centrifugation or filtration which results in the production of artifacts and a loss of a portion of the specimen. Paraffin embedding is then required, followed by the study of the resulting serial histological sections.
In the brush technique a brush, having bristles extending radially from a central support, is inserted into the womb to engage the endometrial tissue. When the brush is withdrawn, tissue clings to the brush. Thereafter, the brush, with tissue clinging thereto, must be placed in a solution to dissolve the bristles thereby leaving the tissue in solution. A centrifugal, or filtering, process follows to separate the tissue from the solution. The tissue can then be analyzed. The brush technique is time consuming and requires that each brush be dissolved which is costly. Also, the time delay between extraction of the tissue from the endometrial cavity and ultimate analysis thereof results in some loss in integrity of the tissue. This could provide less than desirable results in the ultimate tests.
In the jet washing technique, a saline solution is placed in a container, such as a syringe, which is inserted into the cavity. A vacuum reaction results as a suction is produced to suck the saline into the uterine cavity, thereby removing the mucous and exfoliated cells with the washing solution. Since the cells must remain in this solution for variable periods of time, and the solution may not be isotomic, the cells may shrink, or swell producing undesirable artifacts. This methods depends on an airtight system which is not always possible and therefore the entire collecting procedure may fail because no tissue is obtained.
Another technique involves the use of a curette which is inserted into the cavity to draw a sample of tissue from one area of the wall of said cavity. This curette technique does not provide a single sampling of tissue from essentially all areas of the womb and is thereby limiting in its resultant effectiveness. Several samples must be taken from a single patient to obtain a reasonable cross section of the endometrial tissue which lines all areas of the wall of the cavity. Even after all of this is done, there is no absolute assurance that sample tissue has been taken from all areas. This technique can be improved upon if there is a homogenous sampling of the entire surface of the uterine cavity. This technique is usually a hospital procedure and requires anesthesia because it is quite painful. Curettings are limited to histological study and do not adapt to office cytological screenings.
It becomes readily apparent, then, that the preparation, screening and final interpretation of these sections, obtained by presently available techniques, can be costly in terms of time and money. Further the material to be examined ultimately may be questionable in quality and inadequate for meaningful analysis. If the material is not processsed immediately, it becomes pale and washed out. Also, nuclear details are lost and osmotic artifacts may occur. Thus, better-than-average skill is required to prepare readable slides and the cytologist must be deft at differentiating between artifact and real pathology.
In the light of the foregoing, there has existed a dire need for a technique which facilitates direct smearing of the endometrial mucous from the withdrawal instrument onto a slide with rapid fixation to prevent drying and osmotic artifacts. Such a technique would desirably provide a good cross section of the endometrial flora secured on a single slide. This technique would thereby provide a thorough sampling of endometrial tissue from essentially all areas of the wall of the womb and result in a complete examination thereof which is fast and economical.